1. Field of the Invention
This invention relates to computerized systems for accessing information and more particularly to computerized systems for performing research on a body of literature.
2. Description of the Prior Art
The development of random-access mass storage devices for use in computer systems was quickly followed by the development of data base systems which permitted the computer to quickly access information stored in the mass storage devices by means of keys identifying the records in which the information was stored. Query languages in such systems permitted users to specify a subset of the information contained in the data base by specifying one or more keys and operators on the keys. In response to such a specification, the data base system output all records which satisfied the specification. As the cost of mass storage and memory decreased and the power of processors increased, full text retrieval systems were developed in which the data base consisted of text and every word of the text could serve potentially as a key. The query languages in such systems permitted users to specify queries by means of the words in the text and operators which included not only the operators of older data base systems, but also operators specifying information such as the proximity to each other in the text of the words used in the query.
The first-full text retrieval systems were difficult and expensive to use, and were consequently employed principally by specialists such as reference librarians. Moreover, the cost of mass storage was still high enough that individual researchers could not afford enough mass storage to store large text data bases. The full-text retrieval systems thus generally featured large central data bases to which users could gain access by means of telephone lines. As expensive and difficult to use as they were, the first full-text retrieval systems proved so valuable that improved full-text retrieval systems were developed which were designed specifically for use by professionals such as doctors and lawyers rather than librarians.
An example of such a full-text retrieval system is the WESTLAW(.TM.) system, developed by West Publishing Company, St. Paul Minn. WESTLAW is an interactive full-text retrieval system for performing legal research on a large on-line data base of legal documents such as cases and statutes. Users of the system have terminals or personal computers which are connected by telephone to the on-line data base. The user performs research by inputting short commands and queries from his terminal to Westlaw. By means of commands, he specifies a part of the data base such as a reporter for cases decided by a given group of courts. Having done this, he composes a query to be run on the reporter. The system runs the query and makes a list of cases from the reporter which satisfy the query. The list is ordered by the number of times the query is satisfied in the case. The user may access the text of the cases by moving from one location at which the query term appears to the next or by selecting a case from the list and reading that case. Once the user is reading the text of a case, he may move forward or backward from one page to the next. By running a query, reading cases which satisfy the query, using what he learns to refine the query, and running the refined query, the user can define a subset of cases which are exactly "on point" for the legal question he is researching. The user can command WESTLAW to provide part or all of the text of particularly interesting cases, and WESTLAW will send the cases via the telephone line for print out at the user's printer.
While systems such as WESTLAW were successful, the need for telephone line-access to a central data base and the need to memorize commands limited their use. For example, WESTLAW was typically used by research paralegals in large law firms and not by lawyers themselves. These drawbacks were overcome by two developments: powerful personal computers became available at prices which any individual professional practitioner could afford, and CD-ROM optical disks enormously reduced the cost of read-only mass storage. The power of the personal computers permitted better user interfaces to the full text retrieval systems. The CD-ROM disks made text data bases cheaper than books. Every professional user could afford to acquire CD-ROM disks with the information necessary in his field, and the central data bases were now required only for information too recent to be published on a CD-ROM disk. CD-ROM based research systems for personal computers appeared which could be used in the same fashion as WESTLAW, and had such additional features as improved user interfaces employing menus or function keys, "following" a reference embedded in one text to its location in another, output from the optical disks to documents, spreadsheets, or "notepads", and commands permitting users to save the present "state" of a research project so that work could be continued at that point later on. Examples of such CD-ROM based research systems for personal computers include Silversmith, manufactured by Taunton Engineering, Inc., Billerica, Mass., and Research Retrieval and Data Base System, manufactured by TMS, Inc., Stillwater, Okla.
While the CD-ROM based research systems for personal computers overcome many of the cost and ease-of-use difficulties of the on-line research systems, problems remain. Among them are the following: Professional researchers typically do research on several projects at once; present research systems do not accommodate that mode of work. Professional researchers are also typically able to define useful subsets of all of the information in the data base before they begin researching; present systems do not permit him such a definition. Different kinds of research may be more convenient if the same information can be presented in different orders; present systems present the information in a single order. Present systems permit the user to save what he perceives as significant, but users often fail to save what turns out later to be important. Present systems further cannot tailor the manner in which an embedded cross-reference is followed to the user's environment and cannot associate other information which might be valuable to the user of a document with the document. Present systems further do not permit a user to both locate information and work on it within the research system. Moreover, even with the improvements resulting from the availability of personal computers and optical disks, the user interface of present research systems often makes the transition from book-oriented to electronic research more difficult than necessary. It is an object of the invention to provide an improved research system which solves these and other problems of present research systems.